The leader of the largest Iranian opposition group says the country’s current regime “cannot and should not be trusted” and is calling on the U.S. and world powers to recognize Iran's intentions in advance of the deadline on the interim nuclear framework agreement, that comes at the end of this month.

"Nuclear negotiations should compel the Mullahs' regime to abandon its nuclear weapons program. This is the desire of the Iranian people who oppose this program. The Mullahs need the bomb for their own survival," warns Maryam Rajavi, the President-elect of the National Council of Resistance of Iran. 

"No concession should be made to this brutal regime."

Mrs. Rajavi will lead the largest gathering of the Iranian opposition movement in a massive rally outside of Paris Saturday. Her group expects more than 100,000 people to attend the annual day-long event, that will include speeches and protests aimed at sending the world a strong message that permitting Iran to retain any capability to build a possible nuclear bomb is simply unacceptable.

"Do not make more concessions to this regime. Adopt a firm policy and make it clear to the Mullahs ruling Iran that they have to abandon their nuclear weapons program," she told Fox News in an exclusive interview, in which she issued a stark prediction as the talks continue.

Mrs. Rajavi warns that "making more concessions to the regime lays the ground for more instability, and more conflicts and war. U.S. policy has embolden the Mullahs' regime. I warn them that their illusion of changing the behavior of the Mullahs' regime by making concessions to it has already cost the Iranian people dearly, continuing on that path would have serious consequences for the region and the world."

Iran has long denied that it is pursuing a nuclear weapon or has a nuclear weapons program. In 2010, then Iranian President Mahmoud Ahmadinejad told Fox News in an interview that “we do not want an atomic bomb.” Current President Hassan Rouhani has said that Iran is “not after weapons of mass destruction.” In April, Iran’s Supreme Leader Ayatollah Ali Khamenei accused the United States of creating “the myth of nuclear weapons so they could say the Islamic Republic is a source of threat. No, the source of threat is America itself.”

Mrs. Rajavi rejects those claims. She says that the West trying to find a "moderate" in the government is an "illusion," and she brands Tehran "the epicenter of extremism and Islamic fundamentalism" that covets a nuclear ability.

A litany of top former government officials from the United States and other western nations are set to address the gathering in France, including former New York City Mayor Rudolph Giuliani.

"There is only one reason that they are seeking the ability to have nuclear capacity, and that is in order to build a nuclear weapon," Giuliani, a long-time proponent of the Iranian resistance movement, told Fox News.

"There should be support by the United States government for an opposition in Iran. The United States government should support the opposition groups, Mrs. Rajavi's being the most prominent, and the biggest."

Mrs. Rajavi is especially concerned about the prospect that despite the agreement, Iran will ban United Nations nuclear inspectors from its military sites, like the Parchin military complex, and bar interviews with Iranian nuclear scientists.

Last month Supreme Leader Khamenei was quoted as saying that "the impudent and brazen enemy expects that we allow them talk to our scientists and researchers about a fundamental local achievement but no such permission will be allowed...no inspection of any military site or interview with nuclear scientists will be allowed."

"It is absolutely not acceptable," she says of the potential block. "The Mullahs' nuclear program is run by the Revolutionary Guards, so it is impossible to have an effective inspection regime without unconditional access to all military sites.  The military dimensions of the regime's activities are taking place in the military sites."

"A tough inspection regime, which includes access to all suspect sites anytime and anywhere, is necessary to prevent the Iranian regime form obtaining the bomb."

On Wednesday, former Lt. Gen Michael Flynn, who was director of the Defense Intelligence Agency until last year, told a House Foreign Affairs Subcommittee on the Middle East and North Africa hearing, that the nuclear deal being negotiated by the Obama administration, "suffers from severe deficiencies."

Flynn told lawmakers that "Iran has every intention to build an ICBM and a nuclear weapons program.” He warned lawmakers that “believing Iran will change its strategic course is also wishful thinking.”

Since Fox News' first interview with Mrs. Rajavi last year, she has increasingly taken on a higher profile in the United States. In April, she testified before the House Committee on Foreign Affairs, Subcommittee on Terrorism, Nonproliferation and Trade by video-link from France. Her warnings, calling Iran the "godfather" of jihadi terrorism, made headlines from "The New York Times" to the Arabic news service "Al Arabiya." She told lawmakers that the ultimate solution to the Iranian nuclear issue “is regime change.”

"I have no doubt that our goal for a democratic Iran is supported by the American people," she told Fox News.

"Regrettably, the current U.S. policy is misguided, because it refuses to deal with the core of the problem and the source of instability in the region, the Iranian regime. ISIS emerged due to the crimes committed by Bashar Assad in Syria and Nouri Maliki in Iraq, both at the direction of Tehran...recognize that the Mullah's regime in the core of the problem, and not part of the solution. Support the Iranian people and resistance in their struggle for regime change."

The group Mrs. Rajavi leads, also known as the MEK, or People's Mujahadeen Organization of Iran, first opposed the Shah of Iran before turning its focus against the current government. It has long stirred up controversy, having been listed as a terrorist organization for years before finally being delisted by the U.S. and European governments seven years ago. The group's officials blamed Tehran for pressuring Western governments to try and marginalize its efforts. During its struggle, the group says that more than 120,000 of its members have been executed in Iran, with more supporters hanged nearly every week to this day.

Giuliani says Tehran is systematically executing the group's supporters because it is trying to rid the country of potential spies who can reveal its true intentions. The N.C.R.I. first exposed the extent of Iran's secret nuclear program in 2002 and has continued to publicize what it claims are new revelations.

"Iran is tremendously afraid of Madame Rajavi's movement," says Giuliani. "First of all, everyone who belongs to the movement is under a death sentence by the Ayatollah, and he's been killing them. He's been picking them off inside Iran and he's been picking them off, as we have pointed out in the past, in Iraq. He's killed hundreds in Iraq, we don't know how many in Iran but at least that many, and the reality is, Iran is setting us up. Iran is eliminating, over this period of time, the people who would be spies. Iran doesn't want to make the same mistake twice. Last time they reached an agreement of no enrichment, but they enriched, and the spies caught them. This time they are going to reach an agreement about enrichment, and the spies are going to be gone because they are killing them, and we don't seem to want to recognize that."

The Iranian government has branded the N.C.R.I. as "a terrorist" organization, "a cult," and has claimed that its allegations about the Iranian nuclear program have been "fabricated."

But Giuliani compares Mrs. Rajavi's group to other resistance movements like Solidarity, the Polish trade union lead by Leach Walesa, that helped lead to the fall of the Soviet Union.

"We should embrace them, the way we embraced Solidarity during the effort to defeat the Soviets which was so important. We didn't send troops, we didn't send the military. By recognizing Solidarity, we gave them a credibility that eventually led or at least was a part of what led to the demise of the Soviet Union, and it gives us leverage with Iran."

Other supporters, like former Democratic Vice Presidential candidate and Connecticut Senator Joseph Lieberman, say that Mrs. Rajavi and her group promise a new direction for Iran.

"The resistance movement in Iran is our ally...these are our neighbors, these are Iranian Americans and Persian Americans, people from Europe and throughout the world who love their home country and feel that it has been captured by a radical group of Islamist extremists," he told Fox News.

"They are our friends. We share goals with them. They want freedom, they want moderate Islam, they don't want Iran to have a nuclear weapon."

Lieberman, who calls the upcoming agreement a "bad" deal that is like "a piece of Swiss cheese, it's full of holes," also says that the U.S. government should embrace and support Mrs. Rajavi's efforts.

"(She) is very explicit about the importance of Islam remaining moderate and modernizing, and what a message that it is, that this opposition to the Iranian Mullahs is led by a woman, an articulate woman, she is in many ways the moderate leader of Islam that a lot of people in western world have been asking for, pleading for, for quite a long time. She is a democrat with a small 'd,' she believes in democratic elections...we couldn't have better allies in our fight against the Islamic Republic of Iran than the resistance movement of Iran."

Giuliani believes that the Obama administration simply refuses to recognize the Iranian regime for what it is.

"Consider who we are negotiating with," he insists, systematically laying out his case against Tehran like the top federal prosecutor that he once was.

"We are negotiating with an Ayatollah who has killed hundreds of thousands of people, who has dedicated himself openly to the destruction of the state of Israel, who call us devils, who hates Americans. That regime has been responsible for the deaths of hundreds, if not thousands of Americans. During the war in Iraq they were killing American soldiers, there are American families here, in the United States, whose sons and daughters were lost to Iranian Quds force fighters, who were killed by them, and all throughout the Ayatollah has made it clear that they are not going to change the policies of their government. In other words, they are going to continue to be a dictatorship, they are going to continue to be a theocracy, they are going to continue to sponsor Hezbollah, Hamas, the Houthis, and other really horrible terrorist groups. They are going to continue to assassinate and execute people, as they have been  doing now at a higher pace than they did under Ahmadinejad, so we are making an agreement with an entirely, completely reckless and unreliable government. And you don't make agreements with reckless and unreliable governments to give them nuclear weapons."  

For her part, Mrs. Rajavi told Fox News that she believes the same forces that have toppled brutal dictatorships elsewhere will also free the Iranian people.

"We seek an Iran where tolerance replaces intolerance. Love, friendship, forgiveness and compassion will replace hatred, animosity, and brutality. An Iran where women will be free to wear what they like, to study what they like and to engage in any activity they wish. An Iran with gender equality. An Iran where all religious and ethnic minorities will be free and enjoy the same rights as the rest of the people. Just as the late Dr. Martin Luther King spoke of his dream for America, I have a dream for Iran, this is not just a dream. I am confident that Iran will be free soon. Change in Iran is inevitable, because we, the people of Iran, are determined to bring regime change and establish democracy." 

Despite more than three decades of struggle, she remains hopeful.

"The movement is seeking a democratic and non-nuclear Iran, with separation of religion and state, gender equality and regional an international coexistence," she explains.

"The people of Iran are determined to get rid of this regime. I am confident that we will win and the regime will lose."

Fox News' Ben Evanksy contributed to this report.

Follow Eric Shawn on Twitter: @EricShawnonFox